This invention relates to a railroad measuring, gauging, and spiking apparatus.
A common problem in the railroad industry is the tendency of rails to deviate from their proper gauge. Generally speaking, the rails have a tendency to spread apart after trains have repeatedly passed over them. Because of this problem, it is necessary to regauge rails from time to time. It is important that the rails be gauged as accurately as possible both in regauging the rails and in initially laying them.
When rail which has previously been laid is being regauged, it is necessary to remove spikes in tie plates on one of the two rails in the track. Various machines may proceed along a track and remove the spikes to loosen one of the two rails.
Following the loosening of one of the rails, it is necessary to gauge the rail into proper position. Various machines have been used to bring the loose rail into proper gauge with the fixed rail. Once the loose rail is back into proper gauge with the fixed rail it is spiked into position. Typically, the machine which gauges and spikes will then move down four ties from the position which was just spiked and gauge and spike the loose rail at that point. Thus, the loose rail is spiked in proper gauge approximately every four ties after which the intervening ties may be spiked either by the same machine or by a spiker which does not include a gauger or gauging mechanism.
Among the numerous prior art devices adapted for gauging and spiking are those which include measuring devices to indicate the actual gauge of the rail. In theory, the operator can wait until the gauging mechanism has brought the rail into accurate gauge and then activate valves or switches which control the spiking gun or guns on the spiker. However, in actual practice, the operator of the spiking mechanism concentrates on lining up the spikes with the holes in the rail tie plates. Looking up to check the gauge for each tie slows the spiking process down considerably. Accordingly, most operators typically will gauge and spike ten or twelve ties before checking the gauge meter to see if the gauging mechanism is properly bringing the rails to gauge. Not only does this result in a less accurate gauging of the rails then is desirable, but it also slows the operator down since he may have to adjust the gauging mechanism every ten or twelve ties to prevent major errors in gauging.
Thus, a problem typical of prior art gauger and spiker machines is that the operator must visually view the meter in order to determine that the mechanism is properly gauging. If he views the meter quite often, it will take a longer amount of time to gauge and spike a given length of track. On the other hand, if he does not view the meter often enough, the rails will have significant errors in gauging.
Another problem common to prior art gauging and spiking mechanism is that the meter typically gives a gauge measurement for a point significantly removed from the point of spiking. In particular, the spiking guns prevent one from taking a gauge measurement right at the point of spiking. Accordingly, such prior art devices typically will take a gauge measurement at least several inches and possibly more than a foot away from the actual point of spiking. This introduces inaccuracies in the measurement since the point of spiking may be at a different gauge then the place at which the gauge is being measured.
Various types of sensors have been used for measuring the gauge in prior art measuring, gauging, and spiking machines. For example, the use of a linear variable differential transformer (LVDT), have been used for measuring the gauge of rails. Such LVDT's have been used in a telescoping tube having a rail feeler wheel at each end. Since such LVDT devices have a DC output dependent upon the position of a core relative to several coils, the core is movable to change the coupling between the coils depending upon the distance between the rail feeler or gauging wheels. Alternatively, the coils could be movable depending upon the distance between the gauging wheels. In either case, the DC output will be representative of the gauge of the rail at the points of contact of the gauging wheels. The telescoping tube in which the LVDT is mounted extends perpendicular to the rails. A spring may be disposed within the telescoping tube to bias the gauge wheels apart and ensure contact with the rails.
In addition to the problems of slow speed and inaccurate gauging common among prior art machines for the reasons mentioned above, prior art devices have had other problems. For example, although an experienced spiker operator can usually stop the machine so that the spiking guns are positioned adjacent the hole or holes into which spikes are to be inserted, it is usually necessary to move the spiker relative to the vehicle frame in order to position the spiking guns directly over the proper holes. Accordingly, various prior art machines use a spiker which is mounted to move relative to the vehicle main frame. However, since the gauge sensing devices have heretofore been mounted upon the vehicle frame, the distance between the spiking guns and the gauge sensor or measuring device is variable depending upon the position of the spiker relative to the main frame. Accordingly, the accuracy of the measurement may vary significantly.
A further problem common to many prior art machines is that they lack flexibility. That is, they are adapted to run in a prescribed sequence and major efforts are required in order to change the sequence.
Another problem common to many prior art spiking and gauging machines is that a careless operator can spike a rail into an improper gauge without any hindrance from the machine. That is, if the operator simply fails to view the gauge meter, he may spike the rail in place even though the gauge is improper.